Overall, the researchers found that people who had higher levels of both vitamin B6 and methionine were at least 50 per cent less likely to develop lung cancer than those with lower levels of the nutrients. They also found that people with higher levels of folate, vitamin B6 and methionine were two-thirds less likely to develop lung cancer.

Dr Joanna Owens, science information manager at Cancer Research UK, commented: "Although this study suggests a link between vitamin B levels in the blood and reduced risk of lung cancer, this doesn't prove that vitamin B can directly protect against the disease. Vitamin B levels might be higher in people who eat a healthy diet, and this in itself can help reduce the risk of cancer.

"The most important way to prevent lung cancer is to stop smoking. No amount of vitamins can counteract the risks posed by smoking."

Source: Cancer Research UK